Effect of cooking on the bioactive compounds and antioxidant activity in grains cowpea cultivars

The present study evaluated the effect of cooking on the levels of bioactives compounds and antioxidant activity in grains cowpea cultivars. The analysis were performed on the raw samples and after cooking in pressure cooker. Regarding the bioactive compounds present, the grain cultivar BRS Arace exhibited the highest levels of total phenolic compounds (mg/100 g) both before and after cooking, 205.10 +/- 2.89 and 150.62 +/- 2.64, respectively. Spermine and spermidine were identified in the cultivars (mg/kg) BRS Milenio in the amount of 120.5 in crude and 50.4 in cooked grain, in the BRS Tumucumaque in the amount of 116.2 in crude and 47.9 in cooked grain, exhibited significant losses of these compounds after cooking. It was not detected the presence of anthocyanins and flavonoids in the grain cultivars. For the antioxidant activity were observed different behaviors for each grain cultivar in the two methods evaluated. The grain cultivar BRS Arace presented the highest antioxidant activity before cooking according to both methods tested (mu mol TEAC/100 g), 614.7 +/- 5.43 (DPPH) and 660.1 +/- 7.98 (ABTS). The grain cultivar BRS Xiquexique 419.8 +/- 6.80 exhibited the highest antioxidant activity and the grain cultivar BRS Milenio 552.1 +/- 4.78 after cooking. A strong correlation between the antioxidant activity and phenolic content and total flavonoid was found. It is concluded that the grains cultivars maintained important nutritional and functional characteristics following processing, recommending that the cowpea consumption with broth cooking for retaining compounds with antioxidant properties.